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Asymmetrical relationships between absorbance, fluorescence, and dissolved organic carbon 1
Author(s) -
Stewart Arthur J.,
Wetzel Robert G.
Publication year - 1981
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1981.26.3.0590
Subject(s) - dissolved organic carbon , absorbance , chemistry , fluorescence , environmental chemistry , trace metal , metal , gel permeation chromatography , analytical chemistry (journal) , chromatography , polymer , organic chemistry , physics , quantum mechanics
Relationships between ultraviolet absorbance, fluorescence, and concentrations of dissolved organic carbon (DOC) were examined in four model materials fractionated by gel permeation chromatography. Fluorescence was consistently a poor predictor of DOC concentration, and absorbance correctly predicted DOC concentration only in the more labile materials. Asymmetry between DOC and the two optical parameters was related to the apparent molecular weight of the dissolved organic matter (DOM) and could be explained by greater levels of internal quenching and shielding in compounds of larger apparent molecular weight. A lake‐to‐lake comparison ( n = 55) showed a calcium‐related selective loss of high molecular weight humic materials, which invalidates the use of either optical characteristic as a good predictor of DOC concentration in hard‐water systems. Calcium‐related seasonal and between‐lake differences in the relative molecular weight of the DOM may selectively alter trace metal availability.